JPS5837631B2 - magnetic recording and reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION When recording with a magnetic recording/reproducing device such as a tape recorder, the biggest concern is whether the music, etc. to be recorded will fit properly on the tape.

Normally, you have an idea of how long the source you should be recording is, but there is no way to know how many minutes are left on the tape.

Furthermore, when playing a recorded tape, conventionally the player had no choice but to rely on a so-called tape counter to determine what was on which tape.

This will be explained using the most commonly used cassette tape recorder as an example.

The tape counter attached to the cassette deck should mark the beginning of music, etc., and when the set button is pressed, the counter is set to roooJ, and this value increases and decreases and is displayed as the player plays, fast-forwards, and rewinds.

Therefore, after playing, if the counter value reaches ro00J during rewinding, it can be said that the tape has returned to the position when the counter was set, and the counter display value can be used as a guide for the tape position even during the playing.

This counter is normally configured to increase or decrease in proportion to the rotational speed of the hub (tape winding mechanism).

Therefore, when a large number of tapes are wound, the playing time for one Huff revolution is long, and when there are few, the performance time is short.

In other words, the value displayed on the counter is not proportional to the playing time.

The tape counter stops in the playing "stop" state, and when you remove the tape, insert a new tape, and start playing, it will tell you if the new tape you just loaded is the beginning of playing or not.
Regardless of whether it is in the middle or not, start counting from where the count continued at stop 1.

In other words, when the cassette tape is left in the tape counter, the display maintains a relationship with the recorded content and serves as a guide for recording and playback, but once the cassette tape is removed and some operation is performed, there is no relationship between the two. It becomes completely unrelated.

Therefore, it is not possible to locate the recording position based on the previous count number.

In view of these points, the present invention provides a signal related to the rotational speed of the hub on the magnetic tape feeding side or the magnetic tape winding side based on the thickness of the magnetic tape, the amount of feeding of the magnetic tape, or
The present invention provides a magnetic recording and reproducing device that converts the amount of information into the amount of winding and controls the display or drive source in relation to this information. Even if you repeatedly attach and detach the tape, even if you attach a tape that is in the middle of being wound, the elapsed time or
An innovative example that can display the remaining time will be explained in detail.

FIG. 1 is a diagram showing the relationship between a cassette tape tape and a knob.

1 is the take-up side (tape reel), 2 is the feed side huff,
3 is the tape, 4 is the wound tape, 5 is the remaining tape,
6 indicates the tape feeding direction, and when it is in the playing state, this tape moves at a constant speed of VCI 1l/sec (N
O M I N A L S PEED 4.7 5cI
rL/see) in the direction of the arrow.

FIG. 2B shows the rotation detection system.

In the figure, 7 is a hub rotating shaft on the winding side, 8 is a belt, 9 is a pulley, 10 is a mark marked at one point on the winding side rotating shaft, and 11 is a mark sensor.

A mark 10 marked on the winding-side rotating shaft is read by means such as a mark sensor or the like and is converted into a pulse.

As the knob rotates, pulses are generated for each rotation (12 in Figure 2 B).
This will occur as follows.

In FIG. 3, 13 is a reference pulse generated at regular intervals.

12 is a pulse generated every time the knob rotates, as shown in FIG. 2B.

It goes without saying that if the number NPN of the reference pulses 13 included within the 12 pulse intervals is counted, this NPN is proportional to the time required for one rotation of the hub.

In FIG. 2A, the symbols are defined as follows.

ro: Hub radius (diameter at the beginning of tape winding) (constant) rN: Tape radius when the number of windings is N rNt 2 Tape radius when the number of windings is N-1 △: Tape thickness (constant) ※※・1: Winding Current tape length N: Number of windings ■: Tape feeding speed (constant) tN: Time for one rotation of the tape when the number of windings is N tN-K
: Time for one rotation of knob 1 when number of windings is N-K NPN : Number of counts and pulses for one rotation of knob 1 when number of windings is NPN-K: Number of knob 1 when number of windings is N-K Count/pulse number of rotation Z: Count/pulse period How should we define it like this? If we can know the number of windings N, the tape length 1 wound at this time is 2πr, the length of the tape wound at the first O turn is 2π(r+Δ), and so on.
...Because it is 2π(r+N△) in the Nth turn? Established.

■Formula ■In the formula, π, r, Δ, and V are known constants.

Taking a cassette tape as an example, r (hub radius): 1
1. omrrtΔ (tape thickness): 18μrrL (C6
0), 12 μm (C90), or 9 μm (C I
2 0) ■ (Tape speed): 4 7. 5 m
m/sec and Z (count pulse period) are constants that are determined once the device is determined, regardless of tape exchange.

Therefore, the performance time T can be calculated if there is data NPN read every moment during the performance.

That is, in response to the input of data NPN, performance can be achieved by providing an information processing means that executes the calculation shown in equation (2) to obtain N, further executes the calculation in equation (3) to obtain T, and outputs a signal related to this. We can know the time T.

When we actually conducted an experiment based on this principle, we found the following formula:
■Each expression? Then, for a certain tape (for example, a certain C60 tape), find the coefficients α, β, A, and B of the formula ■, which has a small display error of the elapsed playing time T, and use these coefficients to calculate the coefficients α, β, A, and B of the formula When examining the display error of elapsed performance time T for other tapes, the display error increased.

As for the cause of this, it is necessary to examine r, Δ, and ■ in the formula (■).

Considering that ro and V are the same even if the tapes are different, it is considered that the tape thickness Δ influences the display error.

The tape feed speed V is designed to be constant whether the tape is at the beginning, middle, or end of winding, but the running speed may differ slightly depending on the set, so be prepared for such cases. The tape feed speed V is set to full programmer value so that it can be preset or automatically set.

Furthermore, it is convenient and common to set the hub radius r in a preset format.

The object of the present invention is to prevent the influence of errors caused by such factors as tape thickness.

Therefore, the present invention automatically measures the tape thickness, tape running speed, etc., obtains this measured value information, and introduces this information into the control circuit system, thereby preventing errors such as display errors from occurring. By using it, you can achieve this.

Below, the principle of the present invention will be explained using an example in which the influence of errors in tape thickness is eliminated.

In FIG. 2B, when examining the relationship regarding the tape thickness Δ, the following holds true when the tape is wound N times.

By calculating the thickness Δ using the formula ■ and substituting it into the formula ■ or the formula ■ and then the formula ■, the thickness of the tape being actually played can be measured or calculated while being measured, and the playing time T can be found.

The feature of the present invention is that the NPN value is not directly used.
It is also used in the form of NPN-1, that is, the difference from the previous time.

Of course, this difference may be used for accuracy, and may also be used as NPN NPN-K, that is, the difference from K times ago.

(K'''EO, K>0) If the thickness Δ can be measured in this way, the cassette tape is C-60, C-
Since the thickness is standardized as 90 and C-120, it can be used to identify the type of cassette tape and to change the display or program of calculation formulas.
In the present invention, in consideration of the fact that calculating the tape thickness △ simply by one NPNNPN-K may not necessarily provide accurate information, we calculate the average of several measured values. It can also be executed in a form that takes a value.

That is, for example, 20 rotations of the hub from the start of measurement, in other words, the above output from the mark sensor 11 is determined, and the calculated tape thickness Δ is substituted into the equations ■, ■, and ■ as described above. This is applied to calculation of the thickness of the tape during actual performance, and furthermore, to calculation of the playing time T.

Next, an example of FIG. 4 will be described as an embodiment of the present invention.

In this figure, 31 is a cassette tape, and as the cassette tape rotates, a take-up side hub rotating shaft 32 rotates.

The pulse 12 is generated by the mark sensor 33 every time the take-up hub rotating shaft rotates once.

For example, electric pulses can be easily obtained by providing a reflective portion or a transparent portion on a part of the winding-side hub rotating shaft 32 and amplifying the reflected light or transmitted light from the lamp with a phototransistor.

This pulse is input to a reference pulse counter 35 and a microcomputer 36 via a chattering prevention circuit 34 and the like.

It is convenient to use a microprocessor to calculate each of the above equations in this computer, and the microprocessor can perform desired calculations, catch input signals, and output signals using a program (software). Therefore, an example in which a microprocessor is used as the microcomputer 36 will be described here.

Further, the reference pulse counter 35 is connected to the NPN-NPN-
It calculates the average value NT of K and provides the result to the microcomputer 36, an example of which is shown in FIG.

Below, the reference pulse counter 35 shown in this figure will be used as the sixth
This will be explained with reference to the waveform diagram in the figure.

As described above, when the take-up hub 32 rotates based on the rotation of the cassette tape, the mark sensor 33 outputs a pulse 12 indicated by the reference numeral 12 in FIG. The anti-chattering circuit 34 is also input to the counter 35 through the input terminal I1.

At the same time, on the other hand, the clock pulse from the crystal oscillator 39 is suitably frequency-divided by the frequency divider 40, and the reference pulse 13 (reference numeral 13 in FIG. 6) is applied to each counter C1.
It is supplied to C6 to C6 and counted in each.

The pulse 12 that entered the counter 35 through the input terminal
counter (when the reset signal of the microcomputer 36 is inputted through the human input terminal I2, the counter is counted at the start of counting, and then the frequency is divided by 1/10 by the NOR circuit 41, and the counter is counted by the reference numeral 14 in FIG. The pulse output will be as shown in .

Thereafter, the pulse 14 formed by this frequency division further passes through the inverter 42 and enters the JK flip-flop 43.
Here, a down/up signal (indicated by reference numeral 15 in FIG. 6) is generated every 10 pulses 12, that is, every 10 rotations of the hub, and a part of this signal is sent to each of the reference pulse counters C1 to C6. The down/up signal 15 is a signal that increases or decreases the frequency of the reference pulse counter.

), and the other portions are input to the gate 45 after being waveform-shaped by the differentiating circuit 44 in the dashed line area.

In such a state, the reference pulse counters C1 to C6 count down during the first 10 rotations of the hub, and count up during the latter 10 rotations (indicated by reference numeral 15 in FIG. 6). ), and at the timing when the latter 10 rotations are completed, a latch signal (indicated by reference numeral 16 in FIG. 6) is applied from the gate 45 to each of the latch circuits L1 to L6, and each of the reference pulse counters C1 to C6 Latch the contents of.

The point where this latch signal 16 is output (symbol e in FIG. 6)
), a load signal (indicated by reference numeral 1γ in FIG. 6) is applied from the monostable multivibrator 46 to each of the reference pulse counters C1 to C6.

Next, a preset signal (from input terminal I3) is input from the microcomputer 36 to the J-K flip-flop 43, and a latch signal switching signal (from input terminal 4) is sent to the gate 45. There,
The reference pulse counter 35 counts up the reference pulse 13 generated during one rotation of the hub, and then the latch signal is inputted from the microcomputer 36 to the latch circuits L1 to L6 through the input terminal (2), and at that time The contents of is latched, and one measurement operation in the counter 35 is completed.

Simply put, in this reference pulse counter 35, the reference pulses 13, . . . during the first and second half rotations of the hub are as follows
When the addition/subtraction of ... is performed and the contents are latched by the latch circuits L1 to L6, the latched contents are stored in the microcomputer as the average value NT obtained by the above-mentioned formula 0. 36.

Therefore, since the computer (i.e., microprocessor) 36 has a program written in advance, when the average value NT of NPN NPN-K is input, K is set to 10 and the [phase] formula is executed. The program calculates the thickness Δ, stores it in memory, and determines whether this thickness Δ is a C60 tape thickness or a C90 tape thickness.
Alternatively, it is determined whether the tape thickness is C120.

Examples of flowcharts according to this program include those shown in FIGS. 7 and 8.

In Fig. 7, ST is the start, S1 is the rotation time measurement, S2 is the judgment after three measurements, and S3
? memorizes the rotation time, S4 measures the rotation time, S determines whether the measurement has been carried out 10 times, ? 6 memorizes the rotation time,
S7 shows the steps of executing the calculation of Δ (execution of the formula), and S8 shows the storage of the value of Δ.

Also, in FIG. 8, ST1 is the start, and S1 is reading Δ.

S1j S13 j sl4 indicate the respective tapes in which the range of △ is determined, and the 120 minute tapes C1, 90
Minute tape C2, 60 minute tape C3, other tape C4
Determine.

In FIG. 8, Δ: unit is micron.

In this way, by putting the tape in the playing state, the thickness Δ can be automatically measured.

The playing time T can be determined by using the value of this thickness Δ in the programs of formulas (1) and (2).

Determining the thickness △ can be determined at the initial playback stage, so excluding the time until the tape runs stably,
Once you have calculated the thickness △, as long as the thickness does not change during the process, there is no need to successively calculate the number of windings N using the ■ or ■ formula and calculate the elapsed performance time T. The elapsed performance time T can be determined by increasing or decreasing the number of windings per rotation.

If the pulse 12 is taken from the winding side, the elapsed playing (or recording) time can be obtained, and if it is taken from the sending hub, the remaining time (remaining playing time or recording time) can be obtained.

Further, if the playing time of the entire cassette tape is known by determining the type of cassette tape based on the principle of the present invention, the other time can be determined by calculation.

Note that the calculations based on the above formula can be realized using current calculation technology, so a detailed explanation will be omitted.

As described above, the microcomputer 36 outputs a control signal containing information such as the playing (elapsed) time, remaining time, identification of the cassette tape, etc., and operates the display device 47 to display the contents of the control signal.

By including input keys as the input key group 48 that are useful for selecting performance time, remaining time, etc., it is possible to select the performance time, remaining time, etc. according to the input from the input keys, and also to distinguish between tapes. By providing an input key for displaying and other input keys for displaying the content obtained by calculating the above-mentioned formula, display can be performed by operating the corresponding input key.

And 49 is a preset switch, which allows you to preset information such as the speed of tape feeding, the radius above? Information such as "0" and the type of tape can be input to the microcomputer 36 using a preset switch, and is used as input for information processing by the microcomputer 36.

Note that a control signal for the motor 50 is also obtained as an output of the microcomputer 36 to control the rotation system.

In the above embodiment, a case has been described in which the thickness Δ of the tape is measured, but it is also possible to measure the running speed of the tape from, for example, the capstan or an interlocking part linked thereto, and use it as a human power for the calculation of the microcomputer 36. Of course it is possible.

As described above, according to the present invention, when a tape in the middle of a performance is loaded, which was impossible in the past, it is possible to immediately check the elapsed time, not only for a specific tape, but also for a commonly used tape. The remaining time can be obtained as information,
It can be used in a variety of ways, and especially when displayed, it is very convenient for operating a tape recorder.

[Brief explanation of drawings]

Figure 1 shows the relationship between the cassette tape and the hub, Figure 2 shows the relationship between the cassette tape and the hub.
Figure A is a diagram showing the tape winding outer diameter, Figure 2B is a diagram showing the rotation detection system accompanying hub rotation, and Figure 3 is a diagram explaining the waveforms of the reference pulse and pulses output as the hub rotates. , FIG. 4 is a configuration diagram showing an embodiment of the present invention, FIG. 5 is a logic circuit diagram showing a reference pulse counter, and FIG. 6 is a waveform diagram of input and output pulses in each part of this reference pulse counter. FIG. 7 is a diagram showing a schematic flowchart for determining the thickness Δ of the same microprocessor as described above, and FIG. 8 is a diagram showing a schematic flowchart for determining the type of tape. 31: Cassette tape, 32: Mark sensor 35: Reference pulse counter, 36: Microcomputer.

Claims (1)

[Claims] 1. Means for obtaining a signal related to the rotational speed of a hub on the magnetic tape feed side or magnetic tape winding side, and this signal being introduced as an input signal to obtain information related to the thickness of the magnetic tape and adjusting the magnetic tape according to this information. The above-mentioned hub is equipped with an information processing means that outputs a control signal related to information on the amount of tape to be fed or the amount of tape to be taken up, and uses this control signal as a control input for a display device, a drive source, etc. A magnetic recording/reproducing device characterized in that the signal related to the rotational speed is a speed difference between the first half rotation speed and the second half rotation speed of the plurality of rotations of the hub.